Final tune, Need help Options

[Morph914]

Ok , so I have the engine running but it needs tuning. A little background, rebuilt stock 2.0 with D Jet, running a 123 dizzy. It fires right up and idles a little rough at first then smooths out. It revs fairly well and sounds good. The problem starts under load, it starts to stutter a bit.
I have not messed with the adjustment screw on the ECU or tried adjusting the throttle position sensor, or been able to check my fuel pressure.
I’m hoping to rally any troops in the north Florida area to help me get these final details ironed out.

Thanks in advance,
John

[emerygt350]

No kidding. Looks like new. Maybe better.

1 should be fine as long as the port on the distributor isn't going anywhere. Is there a vacuum line on the dizzy? It may not have a port, depends on the model of 123.

[Morph914]

No kidding. Looks like new. Maybe better.

1 should be fine as long as the port on the distributor isn't going anywhere. Is there a vacuum line on the dizzy? It may not have a port, depends on the model of 123.

There is a port on the dizzy, I have been experimenting with it on and off, seems to run better with it off.
The engine is an early ‘73 2.0, it originally had a 1.7

[JamesM]

There is a port on the dizzy, I have been experimenting with it on and off, seems to run better with it off.
The engine is an early ‘73 2.0, it originally had a 1.7

Its probably running better with it off as the 123dizzy should be retarding rather than advancing the timing on vacuum. On a stock setup the vacuum retards the timing at idle and overrun.

Timing should be checked with the vac line disconnected @ 3500 RPM to the 27 deg mark on the fan.

Set the 123 to the A or B curve and make sure the port it is connected to is below the throttle plate, the port that is seeing vacuum at idle. This will most likely cause your idle speed to drop quite a bit which you will need to compensate for by opening the air bypass screw on the throttle body which will then also probably require a minor adjustment to your idle mixture knob as well.

This may help your cold idle as well but...

You mentioned your motor is an early 73, looks like your airbox isnt though so it makes me wonder if you may have other part mismatches going on. Early 73 2.0s I find are a little more temperamental when it comes to parts as they were a very unique setup (hack) from the factory and the temperature curve on the sensor is very different than all other years. Need to be sure your MPS, ECU, and Head Temp Sensor all match for the year, either 73 or 74 and that if they are 73 you also need to be sure you have the inline resistor to the head temp sensor.

[Morph914]

There is a port on the dizzy, I have been experimenting with it on and off, seems to run better with it off.
The engine is an early ‘73 2.0, it originally had a 1.7

Its probably running better with it off as the 123dizzy should be retarding rather than advancing the timing on vacuum. On a stock setup the vacuum retards the timing at idle and overrun.

Timing should be checked with the vac line disconnected @ 3500 RPM to the 27 deg mark on the fan.

Set the 123 to the A or B curve and make sure the port it is connected to is below the throttle plate, the port that is seeing vacuum at idle. This will most likely cause your idle speed to drop quite a bit which you will need to compensate for by opening the air bypass screw on the throttle body which will then also probably require a minor adjustment to your idle mixture knob as well.

This may help your cold idle as well but...

You mentioned your motor is an early 73, looks like your airbox isnt though so it makes me wonder if you may have other part mismatches going on. Early 73 2.0s I find are a little more temperamental when it comes to parts as they were a very unique setup (hack) from the factory and the temperature curve on the sensor is very different than all other years. Need to be sure your MPS, ECU, and Head Temp Sensor all match for the year, either 73 or 74 and that if they are 73 you also need to be sure you have the inline resistor to the head temp sensor.

Ok, so hereis a more detailed description of what I have now. First of all as reported above my MPS is not correct for the 037 ECU that I’m running. So I’m on the hunt for one of those.

Engine is GA000328

MPS is 0 280 100 019 (wrong)

Head temp sensor is 0 280 130 01, on the side it has a #227

Ballast resistor for head temp sensor is 039 971 762A

Fuel pump is a Bosch 69133 unit mounted on lower portion of the firewall



123 dizzy is the 4-R-V- IE unit



I tried to include more pics but unable to pull from the library for some reason.

[JamesM]

Looks like you are missing a digit off your Temp sensor part number, 0 280 130 017 is going to be the part you want to run the 037 ECU on a 2.0 motor. As these were very hard to come by for a long time a lot of them were replaced with 0 280 130 012 (or other) which has the wrong resistance curve and will absolutely impact performance, most notably during warm up. ill have to dig into my parts stash and see if that additional 227 number correlates at all with the bosch PN. You can get by with the wrong CHT sensor but it is far from ideal and you will have idle/warm up issues.

Wrong MPS could for sure be contributing to the stutter under load as this is the sensor the system is the most sensitive to, especially when looking at load vs idle.

Ok, so hereis a more detailed description of what I have now. First of all as reported above my MPS is not correct for the 037 ECU that I’m running. So I’m on the hunt for one of those.

Engine is GA000328

MPS is 0 280 100 019 (wrong)

Head temp sensor is 0 280 130 01, on the side it has a #227

Ballast resistor for head temp sensor is 039 971 762A

Fuel pump is a Bosch 69133 unit mounted on lower portion of the firewall

[Morph914]

Ok, so hereis a more detailed description of what I have now. First of all as reported above my MPS is not correct for the 037 ECU that I’m running. So I’m on the hunt for one of those.

Engine is GA000328

MPS is 0 280 100 019 (wrong)

Head temp sensor is 0 280 130 01, on the side it has a #227

Ballast resistor for head temp sensor is 039 971 762A

Fuel pump is a Bosch 69133 unit mounted on lower portion of the firewall

[/quote

The VW # I have for the head temp sensor is 022 906 041A